In many constructions utilizing power operated drive shafts, it is often desirable to apply a braking action to the drive shaft. This is often under certain conditions such as in the case of a power failure or an emergency stop situation. Heretofore electronic brakes and other types of power brakes have been employed engageable with the power driven shaft for stopping the shaft as desired.
A fail safe brake mechanism is particularly adaptable for use in conjunction with motor operated lift units such as set forth in copending U. S. Pat. application Ser. No. 287,765 filed on July 29, 1981, now U.S. Pat. No. 4,444,540. Such a brake construction would also be adaptable to the power driven shafts employed in electrically driven shuttle units such as disclosed in copending patent application Ser. No. 284,559 filed July 20, 1981.